Microorganisms are living organisms that always exist around us, and there are beneficial microorganisms that help human beings, whereas there are harmful microorganisms that cause problems such as giving rise to disease, creating a bad smell and giving an aesthetic feeling of dislike. In particular, microorganisms may exist in the body such as hair, body, hand, foot and the like due to the external environment, and a large amount of microorganisms may exist even in pet hair and the like. In addition, microorganisms may exist in foods such as vegetables, fruits, fishes, cooking utensils, dishes, or cooking places, and further microorganisms may exist even in toilets. Like this, microorganisms always exist in many places around us.
Therefore, there is a need for an antibacterial agent for sterilizing and cleaning microorganisms for a safe and hygienic life, and various antibacterial agents have been developed accordingly.
On the other hand, an external composition for skin may be contaminated with microorganisms through various routes such as contamination by microorganisms that may occur during the manufacturing process, contamination of bacteria by skin contact of fingers during use, or contamination by water during use.
Therefore, it is required to formulate an antiseptic agent or the like in order to inhibit the growth of microorganisms in the composition or kill the microorganisms and to improve the preservability of the product.
Commonly used antiseptic agents include, for example, paraoxybenzoic acid esters (collectively referred to as “parabens”), imidazolidinyl urea, phenoxyethanol, chlorophenacin or the like. These chemical antiseptic agents may exhibit the effectiveness as antiseptic means for use in the external composition for skin. However, these chemical preservatives formulated in the composition may exhibit skin irritation, allergies, etc., and in severe cases it may exhibit skin toxicity.
It is also possible to prepare an external composition for skin which does not contain an antiseptic agent such as parabens or phenoxyethanol. In such a case, however, a separate measure or device is required for ensuring antiseptic power. For example, it can be aseptically manufactured, or the dosage or the period of use can be restricted. In some cases, it requires complicated means such as the use of a container placed little by little or a container not refilled (for example, a backless tube or a container with a dispenser) is required and thereby there is a problem that it is not economical.
On the other hand, it is known that some diols have an antiseptic power. For example, in the case of 1,2-butanediol and 1,2-hexanediol, the antiseptic power is excellent and thus they are partially used. However, 1,2-butanediol and 1,2-hexanediol have been restricted in their use for preservation of external preparations such as cosmetics due to safety problems such as skin irritation and irritation feeling.